Holding Pakistan responsible for ongoing unrest in the Kashmir Valley, Union Finance Minister Arun Jaitley on Sunday said India's unity has been challenged and the forces behind it need to be defeated. Addressing the BJP's 'Tiranga Yatra' here, the minister said Pakistan was once again at war with India "using new methods" of spreading unrest and inciting violence among masses in the Kashmir Valley. "A new serious situation has arisen. Pakistan and various other forces are involved in it, and the country's unity has been challenged once again, " Jaitley said, adding that people of Jammu and Kashmir should jointly fight against this aggression. "It's a challenge for us. We will not compromise with it, " he added.